Database.Persist.Postgresql

A postgresql backend for persistent.

Documentation

withPostgresqlPool

Arguments

:: (MonadBaseControl IO m, MonadLogger m, MonadIO m)

=> ConnectionString

Connection string to the database.

-> Int

Number of connections to be kept open in the pool.

-> (ConnectionPool -> m a)

Action to be executed that uses the connection pool.

-> m a

Create a PostgreSQL connection pool and run the given action. The pool is properly released after the action finishes using it. Note that you should not use the given ConnectionPool outside the action since it may be already been released.

withPostgresqlConn :: (MonadIO m, MonadBaseControl IO m, MonadLogger m) => ConnectionString -> (SqlBackend -> m a) -> m a

Same as withPostgresqlPool, but instead of opening a pool of connections, only one connection is opened.

createPostgresqlPool

Arguments

:: (MonadIO m, MonadBaseControl IO m, MonadLogger m)

=> ConnectionString

Connection string to the database.

-> Int

Number of connections to be kept open in the pool.

-> m ConnectionPool

Create a PostgreSQL connection pool. Note that it's your responsibility to properly close the connection pool when unneeded. Use withPostgresqlPool for an automatic resource control.

createPostgresqlPoolModified

Arguments

:: (MonadIO m, MonadBaseControl IO m, MonadLogger m)

=> (Connection -> IO ())

action to perform after connection is created

-> ConnectionString

Connection string to the database.

-> Int

Number of connections to be kept open in the pool.

-> m ConnectionPool

Same as createPostgresqlPool, but additionally takes a callback function for some connection-specific tweaking to be performed after connection creation. This could be used, for example, to change the schema. For more information, see:

https://groups.google.com/d/msg/yesodweb/qUXrEN_swEo/O0pFwqwQIdcJ

Since 2.1.3

module Database.Persist.Sql

type ConnectionString = ByteString

A libpq connection string. A simple example of connection string would be "host=localhost port=5432 user=test dbname=test password=test". Please read libpq's documentation at http://www.postgresql.org/docs/9.1/static/libpq-connect.html for more details on how to create such strings.

data PostgresConf

Information required to connect to a PostgreSQL database using persistent's generic facilities. These values are the same that are given to withPostgresqlPool.

Constructors

PostgresConf

Fields

pgConnStr :: ConnectionString

The connection string.

pgPoolSize :: Int

How many connections should be held on the connection pool.

Instances

Data PostgresConf

Read PostgresConf

Show PostgresConf

FromJSON PostgresConf

PersistConfig PostgresConf

type PersistConfigPool PostgresConf = ConnectionPool

type PersistConfigBackend PostgresConf = SqlPersistT

openSimpleConn :: LogFunc -> Connection -> IO SqlBackend

Generate a Connection from a Connection

tableName :: forall record. (PersistEntity record, PersistEntityBackend record ~ SqlBackend) => record -> Text

get the SQL string for the table that a PeristEntity represents Useful for raw SQL queries

fieldName :: forall record typ. (PersistEntity record, PersistEntityBackend record ~ SqlBackend) => EntityField record typ -> Text

get the SQL string for the field that an EntityField represents Useful for raw SQL queries

mockMigration :: Migration -> IO ()

Mock a migration even when the database is not present. This function performs the same functionality of printMigration with the difference that an actualy database isn't needed for it.